This is the Futaba S3154 Digital High-Torque, High Speed Micro Servo for helicopter and airplane use and comes with "J" connector pre-installed. Precision fixed-wing and helicopter flying requires precise, high-tech servos, and we are answering the call with new digital servos that reach full power immediately. They feature high-capacity, high-current wire for low resistance while maintaining standard servo dimensions and light weight so you can mount them almost anywhere.